Semiconductor components, such as chip scale packages, ball grid array (BGA) devices, flip chip devices, and bare dice include terminal contacts, such as contact balls, contact bumps or contact pins. The terminal contacts provide the input/output configuration for a component, and permit the component to be surface mounted to a supporting substrate, such as a printed circuit board (PCB). Semiconductor components also include semiconductor dice, and the terminal contacts can be formed on substrates attached to the dice, or in some cases formed directly on the dice. For some components, such as chip scale packages, BGA devices, and bumped dice, the terminal contacts can be arranged in a dense grid array, such as a ball grid array (BGA), or a fine ball grid array (FBGA).
The terminal contacts are in electrical communication with integrated circuits, and other electrical elements, contained on the dice. Typically the components include patterns of conductors that provide separate electrical paths between the terminal contacts and the integrated circuits. The conductors can comprise metal traces formed on substrates attached to the dice, or formed directly on the dice. The physical and electrical characteristics of these conductors can affect the performance of the component, and the integrity of the signals transmitted through the terminal contacts to or from the integrated circuits on the component.
For example, plating buses are routinely used to electrically connect all of the conductors on a component during the fabrication process. The plating buses facilitate plating of bonding pads for the terminal contacts, and wire bonding pads for wire bonding the conductors to the dice. Following the plating process, the plating buses are trimmed, such that the conductors are no longer electrically connected to one another. However, portions of the plating buses can remain on some of the conductors following the trimming process. These remnant portions of the plating buses add mass and length to the conductors, which can affect electrical characteristics, such as inductance, capacitance and resistance. Other physical characteristics such as overall lengths, location on the component and proximity to other elements can also affect the electrical characteristics of the conductors.
The terminal contacts associated with the conductors will also have different electrical characteristics, and the characteristics of the signals transmitted through the terminal contacts will be different. These signal variations can adversely affect the operation of the integrated circuits on the components, particularly at high clocking speeds (e.g., 500 MHz or greater). It would be desirable to have the capability to adjust the electrical characteristics of the conductors and terminal contacts for semiconductor components, and of other elements of the components as well.
It would be also be advantageous to be able to adjust the electrical configuration of the components as well. For example, it may be necessary to electrically connect or disconnect different terminal contacts on a component to alter the input/output configuration of the component. This may be necessary because standardized components are often fabricated with different types of dice. As such, the configuration of the terminal contacts for a component containing a die with a X4 pin assignment configuration may be different than the configuration required for the same component having a die with a X16 pin assignment configuration. In the prior art different input/output configurations have been achieved by using different layouts for the terminal contacts and the conductors, or by using different wire bonding arrangements between the dice and the conductors.
Also in the prior art, fuses have been used for isolating defective circuitry and for substituting redundant circuitry on a component. For example, a 16 megabit DRAM memory die may have a small percentage of cells that fail following burn-in testing. Fuses can be used to isolate defective integrated circuitry, and to substitute redundant integrated circuitry. Fuses can be controlled using electrical signals, or by using a laser beam directed at a portion of the fuse.
Fuses have also been used in the art to lock in operating clock multipliers for microprocessor components. This type of microprocessor is manufactured by Advanced Micro Devices, Inc. of Sunnyvale, Calif., under the trademark “ATHLON”.
The present invention provides a method for adjusting the characteristics of semiconductor components and elements thereof, and for customizing the input/output and electrical configuration of semiconductor components as well.